Name: WaterBoost Mikrofill 3 Pro + 2 × HWB-INT-200LV Pressurisation Kit
Brand: WaterBoost
SKU: WBPK3P2X200
Price: 2508 GBP
Availability: InStock

WaterBoost Mikrofill 3 Pro + 2 × HWB-INT-200LV Pressurisation Kit

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Established 1975
Trusted by thousands of customers

Mikrofill 3 PRO pressurisation unit + 2 × GWS HeatWave HWB-INT-200LV expansion vessels + 1¼” service valve, for heat pump systems up to 7,720 litres.

A complete set for keeping a large sealed heating system at pressure. The Mikrofill 3 PRO is a pumpless, direct-type unit. It connects straight to the mains, fills the system from empty and tops it up automatically, with WRAS-approved Category 4 backflow protection built in. Two HeatWave HWB-INT-200LV vessels share the expansion as the water heats, and the lockable service valve lets them be isolated and drained for checks.

7,720 L

System size up to

8.7 bar

Max cold fill pressure

2 × 200 L

Expansion vessels

Pressurisation unit

Mikrofill 3 PRO (72846) — made in Britain by Mikrofill

Expansion vessels

2 × HeatWave HWB-INT-200LV — by Global Water Solutions (GWS)

Wall-mounted unit, colour display, leak detection, MODBUS RTU and 4 BMS outputs. Two floor-standing vessels on legs, 10 bar rated, each with an exchangeable membrane. For closed-loop heating and chilled water systems. 2-year warranty on the Mikrofill unit.

Full Description

More about this product

Full Description

What’s in the kit

The WaterBoost Mikrofill 3 Pro + 2 × HWB-INT-200LV Pressurisation Kit brings together four components, matched to heat pump systems up to 7,720 litres:

Mikrofill · made in Britain

Mikrofill 3 PRO pressurisation unit (72846)

Pumpless, direct-type unit with a 3.95″ colour display. Fills and tops up the system straight from the mains, up to 8.7 bar. Supplied with two braided hoses with integrated isolation valves, and a wall backplate.

Global Water Solutions (GWS)

2 × HeatWave HWB-INT-200LV expansion vessels

Two 200 litre vertical heating expansion vessels on legs, each with an exchangeable high-grade butyl membrane. 1¼” BSPT connections, 10 bar, factory pre-charged to 1.5 bar.

Included

1¼” lockable service valve

Isolates and drains the vessels so the pre-charge can be checked, and locks open in normal use.

Why the Mikrofill 3 PRO

No pump, no break tank

It uses the pressure already in the mains or boosted supply, so there’s no pump to wear out and nothing to hear.

WRAS Category 4

Fluid Risk Category 4 backflow prevention built in, WRAS approval 2307805 and Kiwa Regulation 4. No separate RPZ valve needed.

Fills from empty

Up to 12 l/min, with live flow readings to ±3% and a logged fill volume, so you know exactly how much water went in for inhibitor dosing.

Leak detection and smart fault logic

Spots leaks and system faults early, with flood protection by run-time limiter and high/low pressure alarms.

BMS ready

MODBUS RTU and 4 customisable volt-free outputs. Logs up to 100 time-stamped parameter changes and faults.

Compact and sealed

250 × 155 × 290 mm, IP55, wall-mounted on the supplied backplate.

How it’s installed

The two vessels stand side by side on their legs, teed together, and connect to the heating return through the service valve, which is locked open in use. The unit’s system hose connects into the return near the vessels, and its inlet hose takes the mains or boosted cold supply. Mikrofill’s schematic shows a pressure reducing valve on the incoming supply.

The unit’s 22 mm tundish drain goes to a visible discharge point. The safety valve stays on the heat source. Power is 230 V from a 3 A fused spur. Leave 100 mm clear to the left and top, 170 mm to the right, and 750 mm in front of the unit.

Specifications

Kit
Application	Sealed heating and chilled water systems (closed loop)
System volume — heat pump	Up to 7,720 L (60 °C flow)
System volume — boiler	Up to 4,310 L (82 °C flow)
Total vessel volume	400 L (2 × 200 L)
Sizing basis	3 bar safety valve, 1.5 bar vessel pre-charge
Max working pressure	9 bar (set by the unit)
Max system water temperature	85 °C (set by the unit)
Service valve	1¼”, lockable, with drain
Mikrofill 3 PRO (72846)
Type	Pumpless, direct type
Max inlet pressure	9 bar
Max cold fill pressure	8.7 bar
Max operating pressure	9 bar
Max flow rate	12 l/min
Low inlet pressure cut-out	0.3 bar
Backflow protection	WRAS Category 4 (2307805), Kiwa Regulation 4
Display	3.95″ backlit colour LCD
Pressure setting resolution	±0.1 bar
Communication	MODBUS RTU, 4 BMS outputs (5 A max)
Connections	Inlet 15 mm compression; system 15 mm compression; drain 22 mm compression
Supplied with	2 × braided hoses with integrated isolation valves; backplate (fixings not included)
Electrical	230 V / 1 ph / 50 Hz, 3 A fuse
IP rating	IP55
Ambient / inlet / system water temperature	5–45 °C / 5–23 °C / 5–85 °C
Max relative humidity	70% non-condensing
Dimensions (W × D × H)	250 × 155 × 290 mm (386 mm to bottom of tundish)
Weight	5.3 kg (without hoses)
Warranty	2 years
GWS HeatWave HWB-INT-200LV (× 2)
Quantity	2
Nominal volume	200 L each
Type	Vertical on legs, exchangeable membrane
Connection	1¼” BSPT
Max operating pressure	10 bar
Operating temperature	−10 to 99 °C
Factory pre-charge	1.5 bar
Membrane	Exchangeable, high-grade butyl
Dimensions (H × Ø)	1,073 × 590 mm each
Weight	38.2 kg each

FAQs

How do I know 7,720 litres covers my system?

Add up the water in the heat source, buffer tanks, cylinder coils, emitters and pipework. The 7,720 L figure is based on 60 °C flow, a 3 bar safety valve and the vessels’ 1.5 bar pre-charge. For a bigger system, see the Mikrofill 3 Pro + HWB-INT-500LV kit.

Why two vessels instead of one large one?

Two 200 L vessels are 1,073 mm tall and 38.2 kg each, so they fit under lower plant room ceilings and through standard doorways, and each one is a manageable lift. A single vessel of similar capacity is far taller and heavier.

Can I use it on a boiler system?

Yes, up to 4,310 L at 82 °C flow. A boiler runs hotter, so the water expands more and the same vessels cover less.

What does the exchangeable membrane mean?

The membrane inside each vessel can be replaced if it ever fails, so the steel vessel stays in place rather than being scrapped.

What fill pressure can it reach?

Up to 8.7 bar, but never more than your incoming supply. The 3 PRO has no pump, so it uses the pressure already in the mains or boosted supply, and it cuts out if the inlet drops below 0.3 bar. In practice the fill pressure is set well below the heat source’s safety valve.

What’s the service valve for?

It isolates the vessels from the system and drains their water side, so the pre-charge can be checked or a vessel swapped without draining the system. It must be locked open in normal use.

Can I use glycol?

Yes, propylene glycol up to a 50% mix. Don’t use ethylene glycol.

Can this go on a hot water cylinder or a potable system?

No. HeatWave vessels are for closed-loop systems only. For potable hot water, use a GWS ThermoWave vessel.

Downloads

Mikrofill 3 Pro PDF
Download
Data Sheet PDF
Download

Delivery Information

Standard delivery:
Standard delivery is free on most orders. Some items may incur a delivery charge depending on weight, size or value. Any applicable charge will be displayed at checkout.

Deliveries will typically be made between 7am and 6pm, Monday to Friday (excluding public holidays).

Next day delivery:
Next working day delivery is available for a £16.50 + VAT delivery charge.

Orders must be placed before 12 noon to qualify for next working day delivery. Orders placed after 12 noon on Thursday but before noon on Friday will be delivered the following Monday. Orders placed after 12 noon on Friday will be delivered on Tuesday.

Pallet/Large/Difficult items:
Some large, heavy or difficult to transport items may incur an additional delivery charge. Please contact us for a delivery quote before ordering.